Soon after taking office, President Richard Nixon introduced his policy of "Vietnamization." The plan was to encourage the South Vietnamese to take more responsibility for fighting the war. It was hoped that this policy would eventually enable the United States to withdraw gradually all their soldiers from Vietnam.
To increase the size of the ARVN, a mobilization law was passed that called up into the army all men in South Vietnam aged between 17 and 43.
In June 1969, Nixon announced the first of the US troop withdrawals. The 540,000 US troops were to be reduced by 25,000. Another 60,000 were to leave the following December.
Nixon's advisers told him that they feared that the gradual removal of all US troops would eventually result in a National Liberation Front victory. It was therefore agreed that the only way that America could avoid a humiliating defeat was to negotiate a peace agreement in the talks that were taking place in Paris. In an effort to put pressure on North Vietnam in these talks, Nixon developed what has become known as the Madman Theory. Bob Haldeman, one of the US chief negotiators, was told to give the impression that President Nixon was mentally unstable and that his hatred of communism was so fanatical that if the war continued for much longer he was liable to resort to nuclear weapons against North Vietnam.
Another Nixon innovation was the secret Phoenix Program. Vietnamese were trained by the CIA to infiltrate peasant communities and discover the names of NLF sympathizers. When they had been identified, Death Squads were sent in to execute them. Between 1968 and 1971, an estimated 40,974 members of the NLF were killed in this way. It was hoped that the Phoenix Program would result in the destruction of the NLF organization, but, as on previous occasions, the NLF was able to replace its losses by recruiting from the local population and by arranging for volunteers to be sent from North Vietnam.